There is no clear definition of what constitutes Anglo-Welsh poetry, and the term tends to have been replaced by the broader "Welsh writing in English" or Welsh literature in English. It includes poetry written by Welsh people whose first language is English, but it also includes poetry by those born outside Wales, but of Welsh descent, whose work is influenced by their Welsh roots. Glyn Jones, in The Dragon Has Two Tongues, defines Anglo-Welsh writers as "those Welsh men and women who write in English about Wales" (p. 37).

Welsh poetry in English is not necessarily influenced by the historically much longer, and parallel, tradition of poetry in Welsh, but it may be influenced by the English dialects of Wales.

The first-known poem in English by a Welshman was Hymn to the Virgin written c.1470 by Ieuan ap Hywel Swrdwal. Well into the nineteenth century, English was spoken by few in Wales, and prior to the early twentieth century there are only three major Welsh-born writers who wrote in the English language: George Herbert (1593–1633) from Montgomeryshire, Henry Vaughan (1622–1695) from Brecknockshire, and John Dyer (1699–1757) from Carmarthenshire. Such Welsh poets who wrote in the English language tended to imitate the conventions of English verse and only in translations from the Welsh did a national voice succeed in making itself heard. Some see the beginnings of true Anglo-Welsh poetry in the work of poets such as Gerald Manley Hopkins (1844–89), Edward Thomas (1878–1917), and Wilfred Owen (1893–1918).

Alun Lewis (1 July 1915 - 5 March 1944), was a poet of the Anglo-Welsh school, and is regarded by many as Britain's finest Second World War poet.

He was born at Cwmaman, near Aberdare in one of the South Wales Valleys, the Cynon Valley, in the South Wales Coalfield. His father was a school teacher and he had a younger sister, Mair. By the time he attended Cowbridge Grammar School, he was already interested in writing. He went on to the University College of Wales, Aberystwyth and the University of Manchester, Manchester. He was unsuccessful as a journalist and instead earned his living as a supply teacher.

Lewis met the poet Lynette Roberts, whose poem "Llanybri" is an invitation to him to visit her home; but she was married to another poet, Keidrych Rhys. In 1939, Lewis met Gweno Ellis, a teacher, whom he married in 1941. In 1941, he collaborated with artists John Petts and Brenda Chamberlain on the "Caseg broadsheets". Although best known as a poet, his first published work was a volume of short stories, The Last Inspection (1942). In his poem Raider's Dawn Lewis makes a biblical reference to Peter and Paul.

Peter Warlock was a pseudonym of Philip Arnold Heseltine (30 October 1894 – 17 December 1930), an Anglo-Welsh composer (mainly of songs) and music critic. He used the pseudonym (and various others) when composing, and is now better known by this name.

Philip Heseltine was born in the Savoy Hotel in London. His father died when he was only two, and his mother remarried in 1903; she then returned to her native Wales, living at Cefn Bryntalch Hall, Abermule, near Newtown, Montgomeryshire, the family home of her second husband, Walter Buckley Jones. Philip's education was mainly classical including studies at Eton College, at Christ Church, Oxford (for one year), and at University College London (one term). In music, he was mostly self-taught, studying composition on his own from the works of composers he admired, notably Frederick Delius, Roger Quilter and Bernard van Dieren. Nevertheless, one of the masters at Eton, Colin Taylor, had introduced him to some of the modern masters which made a marked impression on him, most notably Delius himself. He was also strongly influenced by Elizabethan music and poetry as well as by Celtic culture (he studied the Cornish, Welsh, Irish, Manx and Breton languages). It was the move to Wales, occasioned by his mother's remarriage, that was the spark for this; Welsh may at that time have enjoyed a relatively low status in the country but Philip, never one to shy away from the unconventional, set about learning it with vigour.

The Anglo-Irish Treaty (Irish: An Conradh Angla-Éireannach), officially called the Articles of Agreement for a Treaty Between Great Britain and Ireland, was a treaty between the Government of the United Kingdom of Great Britain and Ireland and representatives of the secessionist Irish Republic that concluded the Irish War of Independence. It established the Irish Free State as a self-governing dominion within the British Empire and also provided Northern Ireland, which had been created by the Government of Ireland Act 1920, an option to opt out of the Irish Free State, which it exercised.

The treaty was signed in London on 6 December 1921 by representatives of the British government (which included Prime Minister David Lloyd George, who was head of the British delegates) and envoys of the Irish Republic, including Michael Collins and Arthur Griffith, who claimed plenipotentiary status (i.e. negotiators empowered to sign a treaty without reference back to their superiors). In accordance with its terms, the Treaty was required to be, and was, ratified by the members elected to sit in the House of Commons of Southern Ireland and the British Parliament. Dáil Éireann for the de facto Irish Republic also ratified the Treaty. Though the treaty was narrowly ratified, the split led to the Irish Civil War, which was ultimately won by the pro-treaty side.

Gerard Manley Hopkins, S.J. (28 July 1844 – 8 June 1889) was an English poet, Roman Catholic convert, and Jesuit priest, whose posthumous fame established him among the leading Victorian poets. His experimental explorations in prosody (especially sprung rhythm) and his use of imagery established him as a daring innovator in a period of largely traditional verse.